To solve the disadvantage of high cost and low efficiency in the traditional three-way crack detection methods, a three-dimensional crack change detection method based on binocular vision was proposed. Three-dimensional equivalent model of crack change was established, and the calculation of crack changes was equivalent to the calculation of changes between targets. Three-dimensional reconstruction of cracks was carried out through feature point code matching, spatial coordinate system transformation, three-dimensional coordinate calculation, and the three-dimensional situation of the fracture change was obtained. To verify the accuracy of the method, a unidirectional displacement test was carried out. The results show that the maximum measurement error of the opening and dislocation of the crack is within 0.2 mm, and the maximum measurement absolute error of settlement of the crack is within 0.3 mm, which meets the requirements for crack detection in technical specification for earth-rockfill dam safety monitoring.

The local open channels play a certain role in regulating and storing water, but the water flow in the junction section with open channel variation and pressure is relatively complex, which may cause adverse water flow phenomena such as air intake, whirlpool and surges. In order to study the hydraulic pattern of the connecting section between the open channel and the pressurized tunnel, based on the water conveyance tunnel of Wenzhou Oujiang water diversion project, a 30:1 large scale normal local hydraulic model was built according to the gravity similarity criterion. The hydraulic pattern, water surface line distribution, velocity distribution and wave characteristics under different conditions were observed through hydraulic model tests. The flow trend, depth, velocity and wave characteristic parameters under different working conditions were obtained. The research results show that the flow in the open channel and the pressurized junction section through the gradual transition is in good shape, and there is no air intake, backflow and surge, which provides support for the safe operation of the project.

To ensure the safe and stable operation of large radial gate in service, taking the hydraulic radial gate of Gezhouba Project as an example, the finite element analysis software was used to analyze the static strength and modal to obtain the maximum stress concentration point and deformation of the gate under the design head condition. The vibration intensity of the gate was judged according to the natural frequency, vibration model and maximum deformation displacement. The results show that the deviation between the total design water pressure of the gate and the theoretical calculation is 4.7%, which is located in the 5% error control range. The overall maximum stress of the radial gate is 373.86 MPa and the deformation is 12.938 mm, meeting the design requirements of the specification. The bottom of the panel exists local stress concentration, the overall vibration deformation of the gate is less than 0.508 mm, and the vibration intensity is small. Only low-order frequencies appear in the high-energy region of the pulsating pressure of the water flow, and the possibility of resonance is small.

Taking Shiping large irrigation area in Yunnan Province as an example, this paper studied the economic value of irrigation water and analyzed the influencing factors of crops in the irrigation area through the benefit sharing coefficient method and residual value method. It is found that the economic value of irrigation water for cash crops and fruits is higher than that for food crops. At the same time, it is recommended to use the benefit sharing coefficient method to calculate the benefits in irrigation district planning. The results of this study can guide similar irrigation district planning and help the construction of high standard modern irrigation districts.

The tidal river network area has the characteristics of criss-crossed water systems and developed cities. High intensity land use and development leads to serious hydrological pollution and degradation of ecological environment functions of urban landscape lakes. Taking the typical urban landscape lake in the river network area - Baiyun Lake in Guangzhou as the research object, this paper constructed a two-dimensional hydrodynamic and water quality coupling model to study its eco-environmental water demand and its water supplement schemes. The results show that the two-dimensional hydrodynamic and water quality coupling model in the river network area based on Mike21 can effectively simulate the temporal and spatial evolution law of water quality in urban landscape lakes, and the relative errors between the simulated values and the measured values are less than 0.20, Nash efficiency coefficients are greater than 0.75. By jointly using Baiyun Lake sluice and pump hydraulic engineering to dispatch and replenish water, the assurance rates of eco-environmental water demand of Baiyun Lake and its connected rivers are basically 100%, the contents of TN and TP meet the fourth class water quality. The research results can provide reference for ecological and environmental governance of urban landscape lake of polluted river network.

A large area of tensile stress in the middle and lower part of the upstream of a stone-masonry arch dam exceeds the standard and needs to be strengthened. Based on two local reinforcement schemes of a masonry dam, the contact element was used to simulate the joint characteristics of the new and old dam bodies, and the stress and deformation characteristics of the joint surface under five standard working conditions were analyzed. The results show that after reinforcement, the opening and loading characteristics of the joints of the two schemes are similar, and the side pier of the rib pier scheme has asymmetrical opening and loading phenomenon. Under the condition of high water level, the reinforced structure mainly supports the load at the upper part, and the stress at the lower part is small and may open. Under the condition of low water level, the stress level of the joint surface is low and the reinforced structure does not bear the load. Under the condition of temperature drop after reinforcement, the masonry dam body rotates and deforms with the upper part of the reinforced structure as the fulcrum, and the joint surface will open in a large area under the condition of low water level. Under the condition of temperature rise, the dam body shifts upstream when the water level is low, resulting in a symmetrical and smooth parabolic clearance distribution on the horizontal direction.

Dewatering in deep well would lead to the decline of groundwater level and reduce the strength and stability of the soil, which affects the construction safety of the diversion tunnel. In order to study the influence of deep well dewatering on the seepage field of the tunnel during the construction period, a three-dimensional seepage finite element model of Chuanqin tunnel of Xixiayuan water control project and irrigation area project was established. The construction plan of the tunnel and the change of Qinhe water level were considered to analyze the seepage characteristics of the tunnel under the conditions of deep well dewatering and without dewatering. The results show that the dewatering of the deep wells affects the tunnel excavation, changes the potential distribution characteristics of the seepage field around the deep well, forms a falling funnel on the infiltration surface. The water level contour is in a backwater ring near the deep wells. Compared with the deep well without dewatering, the maximum seepage gradient and unit width seepage flow of deep well dewatering are increased by 18.6 times and 3.3 times, respectively, and the seepage stability of soil layer under all working conditions meets the requirements. The research results can provide a basis for the design and construction of similar water diversion projects.

Plain river network, especially near the airport area, has complex hydrological structure, and the flood control and drainage are very important. Taking the Hangzhou International Airport as an example, one-dimensional hydrodynamic model of the river network was built based on MIKE11. The current situation of drainage was analyzed through different startup conditions of the existing drainage pumping station, and the optimization and promotion plan was proposed. The result indicates that the overall drainage capacity of the West Work Area of Hangzhou Airport cannot meet the standard of “once in 20 years”, which needs to be optimized for drainage. Under comprehensive consideration, it is recommended to use strong drainage instead of regulation and storage, and adopt the drainage idea of "mainly strong drainage, combined with regulation and storage" to form an overall drainage pattern of "backbone river channel + strong drainage pumping station".

In order to study the correlation and distribution characteristics of arsenic (As 75) and other trace elements in the water of plateau rivers, the trace elements in the water of Yalong River in July 2021 (wet season) and November 2021 (dry season), an important tributary of the Yarlung Zangbo River, were investigated and analyzed. Based on correlation analysis, cluster analysis and principal component analysis, the relationships among arsenic 75 (As 75), boron 11 (B 11), iron (Fe 57), strontium 88 (Sr 88), tin 118 (Sn 118), lithium 7 (Li 7), vanadium 51 (V 51), cobalt 59 (Co 59), nickel 60 (Ni 60), copper 63 (Cu 63), zinc 66 (Zn 66), selenium 82 (Se 82), molybdenum 98 (Mo 98) and lead 208 (Pb 208) in water were explored. The results show that there are significant differences among the elements in wet season and dry season, which can be divided into three categories: The elements with stable contents in wet season and dry season (Ni 60, Co 59, Cu 63, Li 7, Zn 66); The elements with obvious seasonal variation (Sr 88, V 51, Mo 98, Li 7, Se 82, As 75, B 11, Pb 208); Elements less associated with other elements (Sn 118). In addition, most of the trace elements in the Yalong River Basin are related to Ni 60, Co 59, Cu 63, Li 7 and Zn 66. The study can provide scientific basis for understanding the changes of water environment in the basin and subsequent environmental protection.